diff options
Diffstat (limited to 'qobject/json-writer.c')
| -rw-r--r-- | qobject/json-writer.c | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/qobject/json-writer.c b/qobject/json-writer.c new file mode 100644 index 0000000000..309a31d57a --- /dev/null +++ b/qobject/json-writer.c @@ -0,0 +1,247 @@ +/* + * JSON Writer + * + * Copyright IBM, Corp. 2009 + * Copyright (c) 2010-2020 Red Hat Inc. + * + * Authors: + * Anthony Liguori <aliguori@us.ibm.com> + * Markus Armbruster <armbru@redhat.com> + * + * This work is licensed under the terms of the GNU LGPL, version 2.1 or later. + * See the COPYING.LIB file in the top-level directory. + * + */ + +#include "qemu/osdep.h" +#include "qapi/qmp/json-writer.h" +#include "qemu/unicode.h" + +struct JSONWriter { + bool pretty; + bool need_comma; + GString *contents; + GByteArray *container_is_array; +}; + +JSONWriter *json_writer_new(bool pretty) +{ + JSONWriter *writer = g_new(JSONWriter, 1); + + writer->pretty = pretty; + writer->need_comma = false; + writer->contents = g_string_new(NULL); + writer->container_is_array = g_byte_array_new(); + return writer; +} + +const char *json_writer_get(JSONWriter *writer) +{ + g_assert(!writer->container_is_array->len); + return writer->contents->str; +} + +GString *json_writer_get_and_free(JSONWriter *writer) +{ + GString *contents = writer->contents; + + writer->contents = NULL; + g_byte_array_free(writer->container_is_array, true); + g_free(writer); + return contents; +} + +void json_writer_free(JSONWriter *writer) +{ + if (writer) { + g_string_free(json_writer_get_and_free(writer), true); + } +} + +static void enter_container(JSONWriter *writer, bool is_array) +{ + unsigned depth = writer->container_is_array->len; + + g_byte_array_set_size(writer->container_is_array, depth + 1); + writer->container_is_array->data[depth] = is_array; + writer->need_comma = false; +} + +static void leave_container(JSONWriter *writer, bool is_array) +{ + unsigned depth = writer->container_is_array->len; + + assert(depth); + assert(writer->container_is_array->data[depth - 1] == is_array); + g_byte_array_set_size(writer->container_is_array, depth - 1); + writer->need_comma = true; +} + +static bool in_object(JSONWriter *writer) +{ + unsigned depth = writer->container_is_array->len; + + return depth && !writer->container_is_array->data[depth - 1]; +} + +static void pretty_newline(JSONWriter *writer) +{ + if (writer->pretty) { + g_string_append_printf(writer->contents, "\n%*s", + writer->container_is_array->len * 4, ""); + } +} + +static void pretty_newline_or_space(JSONWriter *writer) +{ + if (writer->pretty) { + g_string_append_printf(writer->contents, "\n%*s", + writer->container_is_array->len * 4, ""); + } else { + g_string_append_c(writer->contents, ' '); + } +} + +static void quoted_str(JSONWriter *writer, const char *str) +{ + const char *ptr; + char *end; + int cp; + + g_string_append_c(writer->contents, '"'); + + for (ptr = str; *ptr; ptr = end) { + cp = mod_utf8_codepoint(ptr, 6, &end); + switch (cp) { + case '\"': + g_string_append(writer->contents, "\\\""); + break; + case '\\': + g_string_append(writer->contents, "\\\\"); + break; + case '\b': + g_string_append(writer->contents, "\\b"); + break; + case '\f': + g_string_append(writer->contents, "\\f"); + break; + case '\n': + g_string_append(writer->contents, "\\n"); + break; + case '\r': + g_string_append(writer->contents, "\\r"); + break; + case '\t': + g_string_append(writer->contents, "\\t"); + break; + default: + if (cp < 0) { + cp = 0xFFFD; /* replacement character */ + } + if (cp > 0xFFFF) { + /* beyond BMP; need a surrogate pair */ + g_string_append_printf(writer->contents, "\\u%04X\\u%04X", + 0xD800 + ((cp - 0x10000) >> 10), + 0xDC00 + ((cp - 0x10000) & 0x3FF)); + } else if (cp < 0x20 || cp >= 0x7F) { + g_string_append_printf(writer->contents, "\\u%04X", cp); + } else { + g_string_append_c(writer->contents, cp); + } + } + }; + + g_string_append_c(writer->contents, '"'); +} + +static void maybe_comma_name(JSONWriter *writer, const char *name) +{ + if (writer->need_comma) { + g_string_append_c(writer->contents, ','); + pretty_newline_or_space(writer); + } else { + if (writer->contents->len) { + pretty_newline(writer); + } + writer->need_comma = true; + } + + if (in_object(writer)) { + quoted_str(writer, name); + g_string_append(writer->contents, ": "); + } +} + +void json_writer_start_object(JSONWriter *writer, const char *name) +{ + maybe_comma_name(writer, name); + g_string_append_c(writer->contents, '{'); + enter_container(writer, false); +} + +void json_writer_end_object(JSONWriter *writer) +{ + leave_container(writer, false); + pretty_newline(writer); + g_string_append_c(writer->contents, '}'); +} + +void json_writer_start_array(JSONWriter *writer, const char *name) +{ + maybe_comma_name(writer, name); + g_string_append_c(writer->contents, '['); + enter_container(writer, true); +} + +void json_writer_end_array(JSONWriter *writer) +{ + leave_container(writer, true); + pretty_newline(writer); + g_string_append_c(writer->contents, ']'); +} + +void json_writer_bool(JSONWriter *writer, const char *name, bool val) +{ + maybe_comma_name(writer, name); + g_string_append(writer->contents, val ? "true" : "false"); +} + +void json_writer_null(JSONWriter *writer, const char *name) +{ + maybe_comma_name(writer, name); + g_string_append(writer->contents, "null"); +} + +void json_writer_int64(JSONWriter *writer, const char *name, int64_t val) +{ + maybe_comma_name(writer, name); + g_string_append_printf(writer->contents, "%" PRId64, val); +} + +void json_writer_uint64(JSONWriter *writer, const char *name, uint64_t val) +{ + maybe_comma_name(writer, name); + g_string_append_printf(writer->contents, "%" PRIu64, val); +} + +void json_writer_double(JSONWriter *writer, const char *name, double val) +{ + maybe_comma_name(writer, name); + + /* + * FIXME: g_string_append_printf() is locale dependent; but JSON + * requires numbers to be formatted as if in the C locale. + * Dependence on C locale is a pervasive issue in QEMU. + */ + /* + * FIXME: This risks printing Inf or NaN, which are not valid + * JSON values. + */ + g_string_append_printf(writer->contents, "%.17g", val); +} + +void json_writer_str(JSONWriter *writer, const char *name, const char *str) +{ + maybe_comma_name(writer, name); + quoted_str(writer, str); +} |